Treadle switches for electronic seaming machines



p 1955 E. P. TURNER ET AL 2,718,566

TREADLE SWITCHES FOR ELECTRONIC SEAMING MACHINES Filed Feb, 11, 1953 r 2 Sheets-Sheet 1 IN V EN TOR. Edgar 1? Werner and/ BY (JUN/o 0729/1??? ATTORNEY p 0, 1955 E. P. TURNER ET AL 2,718,565

TREADLE SWITCHES FOR ELECTRONIC SEAMING MACHINES Filed Feb. 11, 1953 2 Sheets-Sheet 2 INVENTOR. Edgar P Turner and, W y John fl /rr ywi x United States Patent TREADLE SWITCHES FOR ELECTRONIC SEAMING MACHINES Edgar P. Turner, Fanwood, and John A. Herr, Garwood, N. 3., assignors to The Singer Manufacturing Company, Elizabeth, N. 1., a corporation of New Jersey Application February 11, 1953, Serial No. 336,372

6 Claims. (Cl. 200-86.5)

This invention relates to electronic seaming machines of the type which employs a radio-frequency oscillator to furnish the energy for bonding and, more particularly, it relates to a treadle switch for turning on and ofi the oscillator in proper timed relation with the starting and stopping of the feed of material through the seaming machine.

Heretofore it has been customary to employ a switch actuated by the clutch-lever of the conventional electric power transmitter of the clutch-brake type and to carefully adjust the switch for closure just prior to clutch engagement and for opening just after brake engagement, so that the length of scam shall correspond closely to the linear amount of material fed. This has not been completely satisfactory due to the critical switch adjustments required and the necessity of frequent readjustments to compensate for the normal wear of the clutch and brake surfaces.

One of the objects of this invention is to provide a treadle switch for an electronic seamer, which switch shall be actuated by the treadle employed for controlling the clutch and brake operation of the power transmitter for driving said seamer, in order to energize and deenergize the oscillator in a predetermined timed relation to the clutch and brake operation respectively, which relation is substantially unaffected by the wear of the clutch and brake surfaces.

According to the invention, a lost motion connection is introduced between the treadle and the clutch-actuating pitman; and a conventional pressure-sensitive switch is so mounted as to be actuated by the take-up movement in the connection, the switch being effective to turn the oscillator on and ofi.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings,

Fig. 1 is a front perspective view showing the relation between the treadle and the treadle switch embodying the invention.

Fig. 2 is a partial rear elevational view of the devices of Fig. 1 taken in the direction of the arrow 2.

Fig. 3 is a longitudinal view, partly in section, showing the treadle switch assembly.

Fig. 4 is a bottom plan view of the treadle switch assembly.

Fig. 5 is a detailed sectional view taken on line 5-5 of Fig. 3 and showing the switch mounting.

Referring now to Figs. 1 and 2, represents a conventional transmitter-stand pivot bar to which are secured the usual bearing elements 12 and 13 on which is pivoted the usual foot treadle 11. The bearing elements 12 and 13 may be of the type set forth and described in the U. S. patent to Chason, No. 2,557,259, June 19, 1951. A treadle switch assembly indicated generally as 14, and presently to be described, is pivoted on the bearing element 13 fixed to the pivot-bar 10 adjacent to the foot treadle 11. A rod 15 secured horizontally to the rear edge of the treadle by means of clamps 16-16 passes through elongated slotted portions 1717 (Fig. 4) in the switch assembly 14 and terminates in a washer 18 and a tap screw 19. The end of the switch assembly opposite to its pivoted end is connected to a ball-stud 20 forming one element of a ball and socket joint connecting said switch assembly 14 to the regular transmitter pitman 38. The pitman connection may be of the type set forth and described in the U. S. patent to Chason No. 2,478,044, August 2, 1949. A two-conductor electric cable 21 connects the switch of the assembly 14 to the usual electron tube oscillator (not shown) for rendering it efiective or ineffective to instantly supply radio-frequency energy to the seamer in accordance with the operative condition of the switch and in accordance with wellknown oscillator keying methods.

For example, one of the methods for instantly energizing the oscillator is shown and described in the U. S. Patent No. 2,487,432 of November 8, 1949, and com prises a relay for applying A. C. energy to the rectifier tube plates. In'the present case, the switch cable 21 may be connected to control such a relay. Thus, the actual switch employed need be only large enough to handle the small relay current required.

As seen best in Figs. 3 and 4, the switch assembly 14 comprises, preferably, a metal lever 22 of U-shaped or channel cross-section with all of its associated parts located within the confines of the channel. A conventional pressure-sensitive switch 23 is secured between two limbs 24-24 of a lever arm 25 by means of a screw 26. The arm 25 is pivoted about a screw 27 which is secured to the two limbs of the lever 22 and passes through apertured portions of the limbs 24-24 and the switch 23. The end of the lever arm 25 opposite to the switch end is formed with a turned-down tab 28 having a threaded apertured portion 29 for receiving a screw 30 which passes freely through an apertured portion 31 in the top of the lever 22. A compression spring 32 surmounts the screw 30 between the tab 28 and the top of the lever 22 to apply a normal bias pressure to the arm 25.

A leaf spring 33 is secured at one end and to the top of the lever 22 by a screw 34 which passes through an apertured portion thereof and is threaded into a bearing plate 35. The spring 33 is bent intermediate its ends to form a U-shaped portion 44 which partially surrounds the rod 15 and terminates in a flat end portion 36 which rests against a button actuator 37 of the switch 23.

The leaf spring 33 is arranged so that normally, with no foot pressure applied to the treadle 11, the rod 15 is held against the upper walls of the slotted portions 17-17 as seen best in Fig. 3. in this position, the screw 30 is adjusted so that the flat end portion 36 of the spring 33 just rests against the button 37 with the switch 23 in open condition.

The operation is as follows:

When the treadle 11 is depressed to start the machine, the rod 15 overcomes the upward bias of the spring 33 and moves downwardly in the elongated slotted portions 1717 until it contacts the opposite walls of said portions, after which the lever 22 is turned about the pivot bar 10 and operates the pitman 38 which controls the transmitter clutch. The initial part of the downward movement of the rod 15 moves the leaf spring 33 which depresses the button actuator 37 to close the switch 23 in time before the pitman 33 is operated. Further downward movement of the spring 33 forces the switch 23 and its associated lever arm 25 to pivot about the screw 27 and compress the spring 32, and this action avoids any damage to the switch parts. It will be noted from the above that the oscillator will be turned on just before the machine starts, thus insuring good bonding at the beginning of the seam.

When the treadle is released to stop the machine, the pitman 38, under the action of the regular transmitterclutch return spring turns the lever 22 counterclockwise about the pivot bar to its initial position at the start of the operation described above. Thereafter, the spring 33 restores the rod to its original position against the top walls of the slotted portions 17-17 and, in so-doing, the button 37 is released to open the switch 23. In this manner, the oscillator will be turned off just after the machine stops, to insure good bonding all the way to the end of the seam.

The cable 21 may be secured, for strain relief, to an inner surface of the lever 22 by means of a regular cable clamp 39. A rubber grommet 40 protects the'cable on its way through an apertured portion of the lever arm to the screw terminals 46 and 47 of the switch 23 as seen best in Figs. 4 and 5. A plug 41 electrically secured to the end of the cable 21 serves for readily connecting the switch into the oscillator control circuit.

As seen best in Fig. 5, a piece of insulating paper 45 lines the inside of the switch-holding portion of the lever arm 25 to prevent accidental contact of the conductors of the cable 21 with the arm where they are connected to the switch terminals 46 and 47.

For facilitating the attachment of the switch assembly of this invention to machines in the field, the bearing element 13 is formed with a collar 48 and may be slipped on the pivot bar 10 and secured thereto by a set screw 43. This element 13 forms a removable bearing surface for one end of the foot-treadle 11 and for the lever 22, the collar 48 serving to retain the lever closely adjacent the foot treadle.

Having thus set forth the nature of the invention, what we claim herein is:

1. In an electronic seaming machine having an oscillator for supplying radio-frequency energy, an electric power transmitter for supplying the driving power for the machine, a foot treadle for controlling the transmitter, and a clutch-actuating member connected to the transmitter, a switch assembly inserted as a mechanical link between said foot treadle and said member, comprising a supporting member pivoted on a common axis with the foot treadle, a pressure-sensitive switch for controlling the oscillator and mounted on said member, an actuator for said switch, a rod connected to the foot treadle and extending through an elongated apertured portion of said supporting member to contact said switch actuator in operative relation therewith and an operative connection between said pivoted supporting member and said clutch-actuating member whereby movement of the foot treadle actuates the switch and the clutch-actuating member in a predetermined time sequence.

2. In an electronic seaming machine having an oscillator for supplying radio-frequency energy, an electric power transmitter for supplying the driving power for the machine, a foot treadle for controlling the transmitter, and a clutch-actuating member connected to the transmitter, a first lever member pivoted at one end on a common axis with the foot treadle and connected at the opposite end to the clutch-actuating member, a second lever member pivotally secured to the first lever member and spring-biased to a predetermined adjustable position,- a pressure-sensitive switch fixed to said second lever member, a spring actuator for said switch, a rod secured to the foot treadle and extending through an elongated apertured portion of said first lever member to contact said switch actuator whereby operation of the foot treadle actuates said switch and said first lever in sequence to effect the turning on of said oscillator in time before the start of said machine.

3. In an electronic seaming machine having an oscillator for supplying radio-frequency energy, an electric power transmitter for supplying the driving power for the machine, a foot treadle for controlling the transmitter, and a clutch-actuating member connected to the transmitter, a sheet metal member folded to form an elongated channel and mounted to pivot at one end on a common axis with said foot treadle and connected at the other end to the clutch-actuating member, a pressure-sensitive switch pivotally secured to and positioned within the channel, a rod secured to said foot treadle and loosely fitting aligned slots in the limb portions of said channel member to form a lost-motion connection therebetween, a spring actuator for said switch secured to said channel member and positioned to normally urge said rod upwardly to seat against the edges of said slots, and a two-conductor cable electrically connected to said switch and terminating in a plug for ready connection to the oscillator.

4. A switch attachment for an electronic seaming machine having a foot treadle, an electric power transmitter and an oscillator, and adapted to control the turn ing on and off of the oscillator sequentially with the respective clutching and braking of the transmitter, comprising a supporting clement apertured at one end for mounting adjacent to and on a common axis with said foot treadle, and apertured at the other end for connection to the regular clutch lever of said transmitter, a pressure-sensitive switch secured to said supporting element, a spring actuator for said switch, a rod secured to said foot treadle, positioned in operative relation to said actuator and having a limited range of movement relative to said pivoted supporting element for actuating said switch and said clutch lever in a predetermined sequence responsive to operation of said foot treadle.

5. In a switch-supporting assembly, an elongated inverted channel member formed at one end with apertured portions for receiving a pivot bar and at the other end with apertured portions for connecting to motiontransmitting elements, a pressure-sensitive switch secured within said channel member, a leaf-spring actuator for said switch having a portion thereof located adjacent an elongated aperture in said channel member, and an external member reaching through said aperture to engage said actuator to operate said switch and rotate said channel member in a predetermined sequence in response to the movement thereof.

6. A combined motion-transmitting link and electric switch device for insertion between the foot treadle and the clutch-actuating lever of an electric power transmitter to provide switching in a predetermined sequence with the clutch actuation, comprising a supporting member apertured at one end for mounting on a common axis with said foot treadle, and at the other end for connection to said clutch-actuating lever, a pressure-sensitive switch pivotally mounted on said supporting member intermediate its end portions, a leaf spring actuator secured to said member and positioned in operative relation to said switch, said member having an elongated apertured portion giving access to a part of said spring actuator, a rod secured to said foot treadle and positioned to extend through said apertured portion in a loose fit therewith to lie in operative contact with the spring actuator, and electric conductors for connecting said switch to an external circuit.

References Cited in the file of this patent UNITED STATES PATENTS 2,482,550 Koertge Sept. 20, 1949 2,492,347 Ashley Dec. 27, 1949 2,524,026 Best Oct. 3, 1950 

